Implemented a WebClientStub to simplify the unit-test

[demos/testing] / src / test / java / de / juplo / demo / WebClientStub.java

package de.juplo.demo;


import java.net.URI;
import java.nio.charset.Charset;
import java.time.ZonedDateTime;
import java.util.List;
import java.util.Map;
import java.util.function.Consumer;
import java.util.function.Function;
import java.util.function.IntPredicate;
import java.util.function.Predicate;
import java.util.function.Supplier;
import org.reactivestreams.Publisher;
import org.springframework.core.ParameterizedTypeReference;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpMethod;
import org.springframework.http.HttpStatus;
import org.springframework.http.MediaType;
import org.springframework.http.ResponseEntity;
import org.springframework.http.client.reactive.ClientHttpRequest;
import org.springframework.util.MultiValueMap;
import org.springframework.web.reactive.function.BodyInserter;
import org.springframework.web.reactive.function.client.ClientResponse;
import org.springframework.web.reactive.function.client.WebClient;
import org.springframework.web.util.UriBuilder;
import reactor.core.publisher.Flux;
import reactor.core.publisher.Mono;


/**
 * A stub for {@link WebClient}, that can be used for mocking.
 * @author Kai Moritz
 */
public class WebClientStub implements WebClient
{
  public final static WebClientStub WEB_CLIENT = new WebClientStub();
  public final static RequestHeadersUriSpecStub HEADERS_SPEC = new RequestHeadersUriSpecStub();
  public final static RequestBodySpecStub REQUEST_BODY_SPEC = new RequestBodySpecStub();
  public final static ResponseSpecStub RESPONSE_SPEC = new ResponseSpecStub();

  private static Supplier<Mono<?>> TO_MONO = () -> null;
  private static Supplier<Flux<?>> TO_FLUX = () -> null;


  public static void expect(Mono<?> mono) { TO_MONO = () -> mono; }
  public static void expect(Flux<?> flux) { TO_FLUX = () -> flux; }


  private WebClientStub() {}


  @Override
  public WebClient.RequestHeadersUriSpec<?> get()
  {
    return HEADERS_SPEC;
  }

  @Override
  public WebClient.RequestHeadersUriSpec<?> head()
  {
    return HEADERS_SPEC;
  }

  @Override
  public WebClient.RequestBodyUriSpec post()
  {
    return REQUEST_BODY_SPEC;
  }

  @Override
  public WebClient.RequestBodyUriSpec put()
  {
    return REQUEST_BODY_SPEC;
  }

  @Override
  public WebClient.RequestBodyUriSpec patch()
  {
    return REQUEST_BODY_SPEC;
  }

  @Override
  public WebClient.RequestHeadersUriSpec<?> delete()
  {
    return HEADERS_SPEC;
  }

  @Override
  public WebClient.RequestHeadersUriSpec<?> options()
  {
    return HEADERS_SPEC;
  }

  @Override
  public WebClient.RequestBodyUriSpec method(HttpMethod hm)
  {
    return REQUEST_BODY_SPEC;
  }

  @Override
  public WebClient.Builder mutate()
  {
    throw new UnsupportedOperationException("Stub is immutable!");
  }


  public static class RequestHeadersUriSpecStub implements WebClient.RequestHeadersUriSpec
  {
    private RequestHeadersUriSpecStub() {}


    @Override
    public WebClient.RequestHeadersSpec uri(URI uri)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec uri(String string, Object... os)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec uri(String string, Map map)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec uri(String string, Function fnctn)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec uri(Function fnctn)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec accept(MediaType... mts)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec acceptCharset(Charset... chrsts)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec cookie(String string, String string1)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec cookies(Consumer cnsmr)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec ifModifiedSince(ZonedDateTime zdt)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec ifNoneMatch(String... strings)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec header(String string, String... strings)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec headers(Consumer cnsmr)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec attribute(String string, Object o)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec attributes(Consumer cnsmr)
    {
      return this;
    }

    @Override
    public WebClient.ResponseSpec retrieve()
    {
      return RESPONSE_SPEC;
    }

    @Override
    public Mono exchange()
    {
      return WebClientStub.TO_MONO.get();
    }
  }

  public static class RequestBodySpecStub implements WebClient.RequestBodyUriSpec
  {
    private RequestBodySpecStub() {}


    @Override
    public WebClient.RequestBodySpec contentLength(long l)
    {
      return this;
    }

    @Override
    public WebClient.RequestBodySpec contentType(MediaType mt)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec<?> bodyValue(Object o)
    {
      return this;
    }

    @Override
    public <T, P extends Publisher<T>> WebClient.RequestHeadersSpec<?> body(P p, Class<T> type)
    {
      return this;
    }

    @Override
    public <T, P extends Publisher<T>> WebClient.RequestHeadersSpec<?> body(P p, ParameterizedTypeReference<T> ptr)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec<?> body(Object o, Class<?> type)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec<?> body(Object o, ParameterizedTypeReference<?> ptr)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec<?> body( BodyInserter<?, ? super ClientHttpRequest> bi)
    {
      return this;
    }

    @Override
    public WebClient.RequestHeadersSpec<?> syncBody(Object o)
    {
      return this;
    }

    @Override
    public WebClient.RequestBodySpec accept(MediaType... mts)
    {
      return this;
    }

    @Override
    public WebClient.RequestBodySpec acceptCharset(Charset... chrsts)
    {
      return this;
    }

    @Override
    public WebClient.RequestBodySpec cookie(String string, String string1)
    {
      return this;
    }

    @Override
    public WebClient.RequestBodySpec cookies(Consumer<MultiValueMap<String, String>> cnsmr)
    {
      return this;
    }

    @Override
    public WebClient.RequestBodySpec ifModifiedSince(ZonedDateTime zdt)
    {
      return this;
    }

    @Override
    public WebClient.RequestBodySpec ifNoneMatch(String... strings)
    {
      return this;
    }

    @Override
    public WebClient.RequestBodySpec header(String string, String... strings)
    {
      return this;
    }

    @Override
    public WebClient.RequestBodySpec headers(Consumer<HttpHeaders> cnsmr)
    {
      return this;
    }

    @Override
    public WebClient.RequestBodySpec attribute(String string, Object o)
    {
      return this;
    }

    @Override
    public WebClient.RequestBodySpec attributes(Consumer<Map<String, Object>> cnsmr)
    {
      return this;
    }

    @Override
    public WebClient.ResponseSpec retrieve()
    {
      throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
    }

    @Override
    public Mono<ClientResponse> exchange()
    {
      throw new UnsupportedOperationException("Not supported yet."); //To change body of generated methods, choose Tools | Templates.
    }

    @Override
    public WebClient.RequestBodySpec uri(URI uri)
    {
      return this;
    }

    @Override
    public WebClient.RequestBodySpec uri(String string, Object... os)
    {
      return this;
    }

    @Override
    public WebClient.RequestBodySpec uri(String string, Map<String, ?> map)
    {
      return this;
    }

    @Override
    public WebClient.RequestBodySpec uri(String string, Function<UriBuilder, URI> fnctn)
    {
      return this;
    }

    @Override
    public WebClient.RequestBodySpec uri(Function<UriBuilder, URI> fnctn)
    {
      return this;
    }
  }

  public static class ResponseSpecStub implements WebClient.ResponseSpec
  {
    private ResponseSpecStub() {}


    @Override
    public WebClient.ResponseSpec onStatus(Predicate<HttpStatus> statusPredicate, Function<ClientResponse, Mono<? extends Throwable>> exceptionFunction)
    {
      return this;
    }

    @Override
    public WebClient.ResponseSpec onRawStatus(IntPredicate statusCodePredicate, Function<ClientResponse, Mono<? extends Throwable>> exceptionFunction)
    {
      return this;
    }

    @Override
    public <T> Mono<T> bodyToMono(Class<T> elementClass)
    {
      return (Mono<T>)TO_MONO.get();
    }

    @Override
    public <T> Mono<T> bodyToMono(ParameterizedTypeReference<T> elementTypeRef)
    {
      return (Mono<T>)TO_MONO.get();
    }

    @Override
    public <T> Flux<T> bodyToFlux(Class<T> elementClass)
    {
      return (Flux<T>)TO_FLUX;
    }

    @Override
    public <T> Flux<T> bodyToFlux(ParameterizedTypeReference<T> elementTypeRef)
    {
      return (Flux<T>)TO_FLUX;
    }

    @Override
    public <T> Mono<ResponseEntity<T>> toEntity(Class<T> bodyClass)
    {
      return (Mono<ResponseEntity<T>>)TO_MONO.get();
    }

    @Override
    public <T> Mono<ResponseEntity<T>> toEntity(ParameterizedTypeReference<T> bodyTypeReference)
    {
      return (Mono<ResponseEntity<T>>)TO_MONO.get();
    }

    @Override
    public <T> Mono<ResponseEntity<List<T>>> toEntityList(Class<T> elementClass)
    {
      return (Mono<ResponseEntity<List<T>>>)TO_MONO.get();
    }

    @Override
    public <T> Mono<ResponseEntity<List<T>>> toEntityList(ParameterizedTypeReference<T> elementTypeRef)
    {
      return (Mono<ResponseEntity<List<T>>>)TO_MONO.get();
    }

    @Override
    public Mono<ResponseEntity<Void>> toBodilessEntity()
    {
      return (Mono<ResponseEntity<Void>>)TO_MONO.get();
    }
  }
}